Published: October 4, 2013

LONDON — Twitter might have American roots, but the social-networking service is a truly international phenomenon, its filing for an initial public offering shows. And it is banking on growth overseas to fuel its continued expansion.

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The company’s filing Thursday with the Securities and Exchange Commission reports that more than 77 percent of its 218 million monthly average users in the three months through June were outside of the United States.

In its documents for the most anticipated stock sale since Facebook went public last year, the company noted that it was targeting Argentina, France, Japan, Russia, Saudi Arabia and South Africa for faster growth than in the United States.

The company also revealed in the prospectus — the first look at Twitter’s financial health after it announced last month its intent to go public — that it earned far more of its advertising revenue from American users than from foreign users.

Zachary Reiss-Davis, an analyst at Forrester, said the social network would eventually need to show how it could evolve its global advertising efforts and make its offerings more sophisticated.

“Twitter has done a good job of growing its international user base,” he said, “but now it has to work with marketers to create advertising experiences that work for those international users and for marketers.”

Perhaps surprisingly, Twitter’s most active market after the United States is Indonesia, according to Semiocast, a French market research firm. Elsewhere in Asia, Japan and India have also embraced it. In India, Twitter is widely used by Bollywood stars like Amitabh Bachchan, who has 6.5 million followers on the service.

Yet the budding tech giant faces a series of technical challenges in turning user interest into cold cash, ranging from spotty Internet connections to government bans on the service and fast-growing rivals.

The Twitter platform is language-agnostic, meaning there’s nothing to stop someone from broadcasting messages of up to 140 characters in Swahili, Arabic, French or, for that matter, Klingon or Latin. And the use of characters in Japanese and Chinese, for example, means a user can pack more meaning into a tweet than is the case in English.

Analysts say the social network’s uses, ranging from sharing mundane thoughts on local television shows and sports to organizing social protests and political gatherings, has played a major role in its adoption in both emerging and developed countries.

Twitter said in its filing that it intends to “continue to increase the monetization of our platform” by improving its ability to single out users for “promoted” tweets, or ads, and by expanding its outreach to international advertisers. The company said in the filing that 75 percent of its users entered the service through mobile devices during the second quarter and that 65 percent of its revenue came from mobile ads.

But many users in emerging markets still use low-cost phones that are not designed to take advantage of Twitter’s mobile offerings, meaning the quality of its overseas customer base will depend partly on the continued penetration of higher-end smartphones. The company will also likely have to ramp up its global work force as it looks to increasing sell advertising in regions with multiple languages and cultures.

“Twitter is going to need people on the ground to build relationships,” said Ed Barton, a director at the consulting firm Strategy Analytics in London.

Twitter also faces challenges expanding in countries with authoritarian governments. It said in its S.E.C. filing that “we expect to face challenges in entering some markets, such as China, where access to Twitter is blocked, as well as certain other countries that have intermittently restricted access to Twitter.” Such restrictions will remain a risk for the future, it noted.

Twitter’s problems in China are shared by several other Web services, like Facebook and YouTube, and there is little sign that this will change soon.

The Beijing authorities are wary of the potential of social media to be used to rally opposition to the government and have largely limited social media to China-based organizations, like the microblogging site Weibo, that engage in extensive self-censorship.

Twitter also faces competition for people’s time from rival services. Hundreds of millions of Internet users, mostly in Asia, have turned to smartphone-based messaging services like Line, WeChat, WhatsApp and KakaoTalk, which provide free phone calls and chat functions. While these services are private, and most Twitter comments are public, some people use the services in similar ways to communicate with groups of friends.

Advertising on Twitter, still relatively undeveloped even in the United States and other Western markets, is in its infancy in Asia, analysts say.

“It’s a region with a lot of competitive, regulatory and monitoring issues,” said Neha Dharia an analyst at Ovum, a research firm. “I would say they still have a very long way to go in terms of monetizing the user base. Having said that, there is also tremendous potential.”

And while concerns have been raised in the United States about security agencies potentially tracking individuals’ activities on Twitter, analysts say that the company’s American roots give it credibility with some international users, particularly civilians in authoritarian countries.

“For some people outside the U.S., Twitter’s location is perceived as a positive,” Mr. Barton said.

Reporting was contributed by Eric Pfanner from Tokyo; Keith Bradsher from Hong Kong; Gardiner Harris from Delhi; Vindu Goel from San Francisco; Jonathan Gilbert from Buenos Aires; Simon Romero from Rio de Janeiro; and Andrew E. Kramer from Moscow.